Device for temperature and humidity control of air

ABSTRACT

The invention is a device that allows the manipulation of both the temperature and the humidity of air through the temperature control of two fluid volumes, one of which must be water. Air may be pumped or forced through a volume of water to humidify it. That same air may then be passed over a collection of tubing with a high thermal conductivity containing a cold fluid to chill the air and allow condensation to occur. By this method, air will be dehumidified. Dehumidification can be augmented by the addition of a valve to effect pressurization within the device. The air is then passed through a system of pipes that run through the volume of water responsible for humidification to give the air its final temperature. The heating of the two volumes of water can be done through the same means as air is heated in the place of installation.

RELATED PATENTS

The patents listed below were examined to aid in the design for this invention. Any resemblance between the invention of this application and the above named inventions is slight. 5 884 492 March 1999 Zwicky, et al. 5 850 968 December 1998 Jokinen 5 127 233 July 1992 Coffield 4 090 370 May 1978 Vaughan

BACKGROUND OF THE INVENTION

The invention described in this patent application relates to methods of heating or cooling air through a central air system. This invention also relates to devices designed to humidify or dehumidify air.

Many houses and offices have electronic controls that allow the adjustment of air temperature. These controls cue a heating system to operate when the air temp is below a certain value and prompt the engagement of an air conditioner when the temperature is above a certain value. These units are usually (in part or in whole) centrally located inside of a building as the hub of a system of air ducts that supply individual rooms with air that has been heated or cooled. For an invention to be profitable, it must be able to work within a central framework of ducts.

Humidifying and dehumidifying devices, on the other hand, are generally small and portable units designed to work in a single room or area of a building. The limitation in scale of the dehumidification or humidification that can take place is one of the things that this invention hopes to remedy; as the overall comfort level in a building is strongly dependent on the humidity. This is especially obvious in hot and humid climates. Maintaining a level of humidity can also be advantageous in cold climates. Certain health conditions such as dry skin and frequent nosebleed can be aggravated by continuous exposure to very low humidity levels typically found in the continental climates of the northern parts of North America and Eurasia. The benefits of an increased comfort level from humidification or dehumidification of indoor air are often outweighed by the cost of outfitting a building with enough portable units to effectively treat all the air. Coupled with the failure of most units to operate in both humidifying and dehumidifying capacities, the humidity is often left to fluctuate naturally.

The use of water to heat air primarily dates to the use of radiators, which when filled with hot water were very effective at heating the room in which they were located. The shortcoming of this system was that they often worked too well, making a room uncomfortably warm. The system also required the bulky radiators themselves to be placed in each room. These radiator units were also capable of becoming hot enough to cause burns when touched or to damage objects that were mistakenly placed too near to them. The positives of this system were in its simplicity, as well as taking advantage of radiant heat, hence the name. Another useful dimension to these units was they high specific heat of water that filled them. Once heated, moderate amounts of water could easily heat a large area, and the water could be kept warm efficiently.

Attempted solutions to the problem of total climate control have not yet caught on. One reason this may be the case is that too much emphasis is placed on energy efficiency and not enough on the precision of the machinery. U.S. Pat. No. 4,090,370 attempts to humidify air by passing it over a porous, fabric like material that has been sprayed with water. While somewhat effective, it seems that it would be difficult to maintain a constant level of humidity. In the same patent, the air is humidified before it is dehumidified, and this invention adopts a similar strategy. Also in U.S. Pat. No. 4 090 370 condensation is caused by the heat of evaporation of the sprayed water, a method that also lacks accuracy and precision.

BREIF SUMMARY OF THE INVENTION

This invention is a simple solution to the control of the two main variables of air: temperature and humidity. It is one unit designed to replace four (heaters, air conditioners, humidifiers, and dehumidifiers). This invention is designed to work within a central air framework, and therefore is compatible for installation into most buildings. This capability to work as in a central air framework also means that the entire building will have the benefits of the device. If equipped with reasonably sensitive temperature gauges, the invention will be able to exert accurate and precise control over both the temperature and the humidity. This is because water will be used as the main heat transfer medium and its high specific heat allows its temperature to be held nearly constant when its volume is of reasonable size in comparison with the flow rate of air through the machine. The humidity of the air will be manipulated by passing it through a volume of water to absorb moisture and to filter the air, then a, system of cooler piping to remove the moisture, and then the final temperature of the air will be set by piping that is in thermal contact with the first volume of water. The dehumidification of the air can be made to be more complete by the addition of a valve that allows both chambers to be pressurized. The pressurization also gives the unit the ability to sterilize the air by allowing the humidification water to exist at temperatures above 100° C.

BREIF DESCRIPTION OF THE DRAWINGS

FIG. 1

1. air intake

2. air pump or blower

3. control unit

4. humidification vat bypass valve

5. bubbler valves

6. humidification vat filled with water

7. to holding tank

8. from holding tank

9. overflow valve (airtight)

9 a. water input valve

10. insulation

11. air/water valve

12. dehumidification area

13. heat transfer piping

14. to holding tank

15. from holding tank

16. adjustable pressure valve

16 a. exhaust air

FIG. 2

17. to humidification vat

18. from humidification vat

19. to dehumidification piping

20. from dehumidification piping

21. heating coils

22. evaporation coils

23. valve for determining flow rate to each evaporation coil

24. from condenser

25. gas compressor

26. to condenser (usually located outdoors)

27. expansion valve

28. temperature sensor

29. circulation fans or pumps

30. one way valves

31. electrical connection

DETAILED DESCRIPTION OF THE INVENTION

The invention can be best understood as the combination of three different cyclic processes: the air cycle, the water cycle, and the coolant cycle. Each of these cycles will be discussed in detail along with the way interact.

The air cycle begins by taking air into the device (1). This intake is usually located within the building, but fresh air can be introduced from also. When the temperature and/or the humidity of the building is outside a set acceptable range, the control device (3) prompts the operation of an air pump or blower (2) that begins to cycle air through the device. Under the normal operation mode, air is lead to a series of valves (5) located at the bottom of the humidification vat (6). These valves allow air to be bubbled through a vat of water and can humidify or dehumidify the air depending on the temperature of the water and the dew point of the air. Should the bubbles be sufficiently small, the air should be very nearly saturated with water vapor. Opening of the humidification vat bypass valve (4) allows air to skip this step in order to conserve energy when no humidity control is necessary. Air then passes through the air/water valve (11) which is present in combination with thermal insulation (10) between the humidification vat (6) and the dehumidification area (12) to decrease the rate at which these two parts (which are most often at different temperatures) reach thermal equilibrium when air is not circulating. The air/water valve (11) also allows condensed water from the dehumidification area (12) into the humidification vat (6).

The air then moves into the dehumidification area (12). While in the dehumidification area (12), the air makes contact with heat transfer piping (13). The amount of condensation that can collect on these pipes depends on their temperature relative to the humidification vat (4), or, more generally, the dew point of the incoming air. Colder pipes can remove a greater amount of moisture from the air. This process can be augmented by an adjustable, pressure sensitive valve (16), that allows for greater air pressure.

From the dehumidification area (12), air then moves into piping that leads through the humidification vat (6). If that piping is of a large enough surface area, the air that passes through it should be in thermal equilibrium with the surrounding water in the humidification vat (4). Air then exits the device (16 a) and enters the ductwork of the building. The motion of air throughout the building can be expedited by the use of fans at this stage.

The water cycle is the process by which water heated and cooled. This water is used as the primary heat transfer medium in the air cycle. The heating and cooling of water takes place in a holding tank where heating coils and the evaporation coil of a heat pump is located. Fans or other methods of moving the water (29) keep the water at nearly the same temperature throughout its continuous fluid volume, including that which is transferring heat to or from the air within the unit.

The water level of the humidification vat (6) can vary, so an airtight water overflow valve (9) must be introduced, as well as a water input valve (9 a). Thermal sensors (28) that are connected to a control unit not pictured in the drawings turn on electric heating coils if a particular water volume is colder than the settings specify. Should the water become warmer than the specified settings, the coolant cycle must be used.

The coolant cycle is not unlike a common air conditioner unit with the evaporator located in thermal contact with the holding tanks, and the condenser located in a heat sink (usually the outdoors). The coolant cycle has a gas compressor (25) that aids in the liquefaction of the coolant gas and an expansion valve (23) that leads into the evaporator. One of the differences in the mechanism is that the expansion valve can divide the fluid moving to either of the evaporators (22) in any proportion. In other words, when only one holding tank needs to be cooled, this valve can exclude the other holding tank from the cooling process. The other difference between the coolant cycle used here and other air conditioners is that the gasses that have passed through the evaporators must pass through one way valves (30) on their way to the compressor. These valves exist to prevent the flow of gasses into an evaporator for which they were not intended.

In summary, the invention described works to independently heat or cool 2 liquid volumes, one of which is water. Air then thermally contacts these liquid volumes and its temperature and humidity is changed. Air is first humidified by bubbling it through a volume of water, then dehumidified by thermal contact with pipes colder than the volume of water. The air stream is then directed back through the volume of water where it achives its final temperature before being ejected from the machine. 

1. A device that controls both the temperature and the humidity of air through the temperature control of two or more fluid volumes, one of which is water.
 2. The invention as set forth in claim 1 and comprising of a section that humidifies air by pumping or blowing air directly through a liquid volume of water, the volume of which is held relatively constant by means of airtight water overflow valves and a connection to a water line coupled with a valve that prompts the filling of the section when the water level is below a set value, and the vat in which the water is contained has valves that allow air to enter and bubble through but do not allow water to escape.
 3. The invention as set forth in claim 2 and comprising of a section containing piping of an appreciable thermal conductivity that can be used as a means of heat transfer, positioned to allow any condensate that forms on it to flow into the section responsible for the humidification of the air stream or out of the unit.
 4. The invention as set forth in claim 3 and comprising of a duct that carries air from the section containing heat transfer piping into a chamber where its temperature can be other things, a refrigeration unit that incorporates a two or thee way valve leading to its evaporation coils.
 5. The invention as set forth in claim 4 and having the ability to be attached to a duct or system of ducts of some kind to aid in the movement of air that has passed through the unit.
 6. The invention as set forth in claim 5 and comprising of a temperature sensitive control system that maintains the preset temperature of the two heat transferring fluid volumes within a set range, by means of a single heat pump that has two evaporation tubes, each in thermal contact with one of the aforementioned fluid volumes and valves that allow the fluid within the heat pump to be split between the evaporation tubes in any proportion and by means of two heating elements of some kind, each in thermal contact with one of the aforementioned fluid volumes.
 7. The invention as set forth in claim 6 and comprising of a sensor external to the unit that triggers the operation of the air pump or blower when the temperature and/or humidity deviates from preset values by a set degree.
 8. The invention as set forth in claim 7 where the method of changing the temperature of the air to its final temperature is thermal contact with the vat of water used to humidify the air stream.
 9. The invention as set forth in claim 7 and comprising of a duct to direct airflow from the intake air mover into the condensation section, bypassing the humidification section of the device.
 10. The invention as set forth is claim 7 and comprising of an adjustable, pressure sensitive valve designed to increase the pressure inside the device while still allowing air to flow through the machine.
 11. The invention as set forth in claim 7 and having the ability to sterilize the air stream flowing through it by heating and pressurizing the air as well as the heat transfer fluids.
 12. The invention as set forth in claims 1-11, or as set forth in any claim numbered 8-11, or as set forth in any combination of claims 8-11. 